Leukotrienes are potent pro-inflammatory mediators that are synthesized by certain bone-marrow derived granulocytes after activation (Samuelsson, Science 220:568, 1983; Lewis et al., J. Clin. Invest. 73:889, 1984). Leukotrienes have been postulated to play an important role in bronchial asthma (Margoskee, Ann. NY Acad. Sci. 629:148, 1990) and in other inflammatory diseases, such as ulcerative colitis, bronchitis, sinusitis, psoriasis, allergic and non-allergic rhinitis, lupus, and rheumatoid arthritis. 5-lipoxygenase is the first committed enzyme in the pathway leading to leukotriene synthesis and is responsible for the conversion of arachidonic acid to LTA4 via the unstable intermediate 5-hydroperoxy eicosotetraenoic acid (Samuelsson et al., Science 237:1171, 1987; Samuelsson, Science 220:568, 1983).
It has been established that treating patients with agents that have the capacity to inhibit 5-lipoxygenase results in improvement in lung function, reduction in asthma symptoms, and decreased need for alternative asthma treatments (Persson et al., Anesthesiology 82:969, 1995; Israel et al., Ann. Int. Med. 119:1059, 1993). Treatment with 5-lipoxygenase inhibitors can also benefit ulcerative colitis patients (Laursen et al., Lancet 335:683, 1990) and those suffering from rheumatoid arthritis (Weinblatt et al. J. Rheumatol. 19:1537, 1992). However, at least in the context of asthma, not all patients experience beneficial effects; there is a heterogenous response in the patient population to treatment with 5-lipoxygenase inhibitors. Prior to the present invention, the reason for this heterogeneity was not known. Moreover, there is currently no way to identify in advance those patients who will respond well, and those who will respond poorly, to 5-lipoxygenase inhibitor treatment. Accordingly, there is a need for improvements in the area of patient response. There is also a need for further analysis of 5-lipoxygenase gene regulation.
The present invention encompasses the discovery that polymorphisms in 5-lipoxygenase gene exist within the general population and, in particular, within the asthmatic population. According to the present invention, such polymorphisms can be correlated with asthmatic phenotype (i.e., susceptibility to asthma and/or severity of disease) and/or with responsiveness to asthma therapies. The present invention therefore provides methods of asthma diagnosis and therapy. Furthermore, the teachings of this invention can readily be generalized to other inflammatory diseases that involve 5-lipoxygenase (e.g., ulcerative colitis, bronchitis, sinusitis, psoriasis, allergic and non-allergic rhinitis, lupus, rheumatoid arthritis, etc.).
Description and characterization of certain of the 5-lipoxygenase gene polymorphisms described herein reveal that different individuals have different capabilities for 5-lipoxygenase expression. Furthermore, differences in 5-lipoxygenase gene expression account for different degrees of patient responsiveness to 5-lipoxygenase inhibitors. Specifically, the present invention demonstrates that those patients who express reduced levels of 5-lipoxygenase, as compared with patients with normal 5-lipoxygenase gene expression (which patients are sometimes referred to as xe2x80x9cnormal controlsxe2x80x9d), show less responsiveness to treatment with 5-lipoxygenase inhibitors; conversely, those patients who express increased levels are more responsive to such treatment. Similar correlations can be expected for other agents that interfere with the leukotriene metabolic pathway (e.g., leukotriene receptor antagonists, 5-lipoxygenase activating protein inhibitors, etc.).
Accordingly, preferred embodiments of the present invention include methods of identifying patients who are likely to be more (or less) responsive to treatment with 5-lipoxygenase inhibitors, as compared to normal controls which methods involve identifying those patients with increased (or decreased) capability for 5-lipoxygenase expression. Analogously, the present invention provides methods defining treatments most likely to be effective for patients with altered 5-lipoxygenase gene expression and/or activity. These findings are applicable to all inflammatory diseases in which treatment with 5-lipoxygenase inhibitors (or related agents) is appropriate and, in particular, are applicable to asthma.
The present invention provides a method of classifying patients suffering from an inflammatory disease which method comprises steps of i) identifying in DNA from at least one patient a sequence polymorphism, as compared with the normal 5-lipoxygenase gene SEQ ID NO:1, in a 5-lipoxygenase gene regulatory sequence; and ii) classifying the patient based on the identified polymorphism.
The invention also provides a method of identifying an asthma patient who is a candidate for treatment with 5-lipoxygenase inhibitors, which method comprises steps of i) identifying a normal control individual who does not have asthma; and ii) identifying an asthma patient who expresses 5-lipoxygenase at a level higher than that at which the normal control expresses 5-lipoxygenase, which asthma patient is therefore identified as a candidate for treatment with 5-lipoxygenase inhibitors.
The invention further provides a method of identifying an asthma patient who is not a candidate for treatment with 5-lipoxygenase inhibitors, which method comprising steps of i) identifying a normal control individual who has normal levels of 5-lipoxygenase gene expression; and ii) identifying an asthma patient who expresses 5-lipoxygenase at a level lower than that at which the normal control expresses 5-lipoxygenase, which asthma patient is therefore identified as not being a candidate for treatment with 5-lipoxygenase inhibitors.
Additionally, the invention provides a method of identifying an individual who is susceptible to an inflammatory disorder, which method comprises steps of i) providing a nucleic acid sample from an individual; and ii) detecting in the nucleic acid sample a 5-lipoxygenase gene polymorphism that correlates with the inflammatory disorder with a P value less than or equal to 0.05, existence of the polymorphism being indicative of susceptibility to the inflammatory disorder.
The invention also provides a method of classifying an asthma patient as suffering from asthma, which method comprises steps of i) providing a nucleic acid sample from an asthmatic individual; and ii) detecting in the nucleic acid sample a 5-lipoxygenase gene polymorphism that correlates with asthma with a P value less than or equal to 0.05, existence of the polymorphism being indicative of asthma.
The invention also provides a method of treating inflammatory disorder patients which method comprises i) identifying in genetic material of one or more inflammatory disorder patients a 5-lipoxygenase gene polymorphism that correlates with increased responsiveness to a therapeutic as compared with responsiveness of an individual lacking the polymorphism; and ii) administering the therapeutic to the patient.